diff options
| author | Peter Hutterer <peter.hutterer@who-t.net> | 2016-11-21 08:39:47 +1000 |
|---|---|---|
| committer | Peter Hutterer <peter.hutterer@who-t.net> | 2016-11-23 10:42:57 +1000 |
| commit | cfdaaa32a73ba2f7b0379c2dbccabf120db8fc5e (patch) | |
| tree | 931583ffd845df239f85341b77546cf9b51e1ec9 | |
| parent | ab83c8e6267b9df5ab383e70e25e4d050a153601 (diff) | |
touchpad: only use the last two coordinates for delta calculation
Taking the last 4 points means factoring in a coordinate that may be more than
40ms in the past - or even more when the finger moves slowly and we don't get
events for a while. This makes the pointer more sluggish and slower to catch up
with what the finger is actually doing.
We already have the motion hysteresis as a separate item to prevent jumps (and
thus adds some delay to the movement), the calculation over time doesn't
provide enough benefit to justify the sluggish pointer.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
| -rw-r--r-- | src/evdev-mt-touchpad.c | 20 |
1 files changed, 5 insertions, 15 deletions
diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c index d72cb191..7b8514cb 100644 --- a/src/evdev-mt-touchpad.c +++ b/src/evdev-mt-touchpad.c @@ -262,29 +262,19 @@ tp_end_sequence(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time) tp_end_touch(tp, t, time); } -static double -tp_estimate_delta(int x0, int x1, int x2, int x3) -{ - return (x0 + x1 - x2 - x3) / 4.0; -} - struct normalized_coords tp_get_delta(struct tp_touch *t) { struct device_float_coords delta; const struct normalized_coords zero = { 0.0, 0.0 }; - if (t->history.count < TOUCHPAD_MIN_SAMPLES) + if (t->history.count <= 1) return zero; - delta.x = tp_estimate_delta(tp_motion_history_offset(t, 0)->x, - tp_motion_history_offset(t, 1)->x, - tp_motion_history_offset(t, 2)->x, - tp_motion_history_offset(t, 3)->x); - delta.y = tp_estimate_delta(tp_motion_history_offset(t, 0)->y, - tp_motion_history_offset(t, 1)->y, - tp_motion_history_offset(t, 2)->y, - tp_motion_history_offset(t, 3)->y); + delta.x = tp_motion_history_offset(t, 0)->x - + tp_motion_history_offset(t, 1)->x; + delta.y = tp_motion_history_offset(t, 0)->y - + tp_motion_history_offset(t, 1)->y; return tp_normalize_delta(t->tp, delta); } |